Based on the text, why is it considered inadequate to compare Sai Baba to the sun or the moon?

In Chapter 50, the author Hemadpant attempts to describe Sai's greatness through comparisons but finds them lacking. He explicitly states that it is not fitting to compare Sai to the sun, because the sun eventually sets. Similarly, if he compares Sai to the moon, that comparison also fails because the moon wanes and is not always full. In contrast to these celestial bodies which have cycles of diminishing, the chapter concludes that Sai is 'forever complete.' This highlights Sai's eternal and unchanging nature, which transcends the limitations of worldly analogies.